Insurance firms in particular will always want to be located in close proximity to Lloyd's of London, meaning the options they have available to them are limited. In addition, the lack of development land in the City has become a major constraint on the number of new blocks going up.

Vydra said that in addition to the lack of supply helping keep rents up, occupiers have also realised that the fundamentals of the UK economy have remained strong in the months following the vote. With pivotal elections looming across the continent, uncertainty has also started to loom over other European markets, making the UK seem attractive in comparison.

Last October, Axa Investment Managers confirmed 22 Bishopsgate will be going ahead. The development of the 62-storey tower had been put on hold due to the EU referendum.